Initially created by Roman Masek in Feb 2009. The last build (version 1.1.5) was released on to the app store back in 2011 and has not been updated since 2012.
This fork of the original opensudoku was created with the intention of keeping the codebase working with more recent versions of the Android API's and build tools.
The project structure has been updated to build with Gradle (the default for Android Studio projects) and now targets API 21 (Android 5.0.1).
Open Sudoku is a fork that started in 2014 and is maintained by Óscar García Amor. Also available on the Google Play Store.
Files pencil_disabled.png and pencil.png are distributed under Creative Commons CC Attribution-Noncommercial-Share Alike 3.0 license.
They are originally created by Paul Davey (Mattahan) and available from IconArchive.